Alignment of lens and image sensor

ABSTRACT

Embodiments related to the alignment of a lens with an image sensor in an optical device are disclosed. For example, one disclosed embodiment comprises an optical device including a printed circuit board, and an image sensor package mounted on the printed circuit board, wherein the image sensor package includes an image sensor. The optical system further comprises a lens holder including a lens, and one or more alignment features arranged on the lens holder. The one or more alignment features are configured to contact the image sensor package to mechanically align the lens holder with the image sensor package.

BACKGROUND

The manufacture of optical devices such as cameras may involve alignmentof optical elements that are mounted on a printed circuit board. Forexample, a lens may be aligned with an image sensor via mounting holesfor each of these components on the printed circuit board. However,printed circuit boards may be low-precision parts that are manufacturedwith loose tolerances. Therefore, in order to ensure proper alignment ofoptical elements mounted to a printed circuit board, an active alignmentprocess may be utilized such that a position of an optical element isadjusted while the optical system is “live” (i.e. while the image sensoris actively acquiring images).

However, such active alignment may be complex and require a high levelof skill, and therefore may lead to increased manufacturing costs.Furthermore, the alignment process may lead to deformation of thecircuit board upon which the elements are mounted, thereby negativelyaffecting the quality of the electronics.

SUMMARY

Accordingly, various embodiments are disclosed herein that relate toaligning optical elements mounted on a printed circuit board. Forexample, one disclosed embodiment comprises an optical system includinga printed circuit board, and an image sensor package mounted on theprinted circuit board, where the image sensor package includes an imagesensor. The embodiment further comprises a lens holder including a lens,and one or more alignment features arranged on the lens holder. The oneor more alignment features are configured to contact the image sensorpackage to mechanically align the lens holder with the image sensorpackage.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of a use scenario of adepth-sensing camera.

FIG. 2 is a schematic side view of an embodiment of an optical systemduring a lens holder installation and alignment process.

FIG. 3 is a schematic side view of an embodiment of an optical systemafter installation of the lens holder.

FIG. 4 is a flowchart illustrating an embodiment of a method foraligning optical components mounted to a printed circuit board.

DETAILED DESCRIPTION

As described above, aligning optical components that are mounted to aprinted circuit board may pose various challenges. For example, due tothe nature of the printed circuit board manufacturing process, it may bedifficult to form mounting holes for a lens and image sensor withdesired tolerances, even where a lens holder used to hold the lens andthe package for the image sensor are themselves precision parts.

Therefore, embodiments are disclosed herein that are related to mountingand aligning an image sensor and associated lens holder onto a printedcircuit board with sufficient precision that subsequent active alignmentsteps (e.g. manual adjustment of the lens while the image sensor islive) may be avoided. Before discussing these embodiments, an exampleoptical device is shown in FIG. 1 in the context of a user 102 playing avideo game in front of a computing system 104 having an embodiment of adepth-sensing camera 106. Images from the depth-sensing camera 106 maybe used by the computing device to detect the user's movements, and toprovide transform the movements into graphical movements of an avatar ofthe player on the display 108. In this manner, the user 102 may controlplay of the video game through body movements alone, without the use ofany hand-held controller or other such device.

The depth-sensing camera 106 may include a plurality of optical elementswhich are aligned in order to detect the user's movements. Such opticalelements may include, but are not limited to, an image sensor mounted toa printed circuit board, and a lens or system of lenses to focus animage of the user onto the image sensor. FIG. 2 shows a schematicdepiction of an embodiment of such an optical system 200. The depictedoptical system 200 includes a printed circuit board (PCB) 202, and animage sensor package 204 mounted on the printed circuit board 202,wherein the image sensor package 204 comprises an image sensor 206.Image sensor 206 may be any suitable type of image sensor, including butnot limited to a complementary metal-oxide-semiconductor (CMOS) sensor.

The image sensor package 204 also includes various geometrical sensorpackage features. For example, the image sensor package 204 may includean image sensor package cover plate 208, and/or a datum corner 210. Suchgeometric features may be configured to have a precise geometricalignment relative to the image sensor 206. As such, the tolerances ofthe geometric features of the image sensor package 204 relative to theimage sensor 206 may be tighter than the tolerances of the geometricfeatures of printed circuit board that holds the image sensor 206.

Continuing with FIG. 2, a lens holder 212 is shown (e.g., a lens barrelholder), wherein the lens holder includes one or more lenses (notshown). The lens holder 212 also may be constructed with tightgeometrical tolerances, such that variation of the position of the lensis very small between lens holders.

In light of the tight geometric tolerances of the lens holder 212 andthe image sensor package 204 compared to the printed circuit board 202,a lens may be aligned with an image sensor in a more precise mannerwhere the lens holder 212 references the image sensor package 204directly, rather than referencing mounting holes in the printed circuitboard.

Accordingly, the lens holder 212 comprises alignment features that areconfigured to contact geometric features of the image sensor package 204to thereby mechanically align a lens within the lens holder 212 with theimage sensor 206 on the image sensor package 204. In this manner, directcontact between parts constructed with tight geometric tolerances isused to align the parts, rather than mutual contact with an interveningstructure (printed circuit board) that has looser tolerances.

Any suitable structures may be used as mounting features to facilitatethe alignment of the lens holder 212 to the image sensor package 204.For example, in the depicted embodiment, a recessed portion 214 of thelens holder 212 comprises one or more protrusions, such as firstprotrusion 216 and second protrusion 218, extending from an insidesurface of the recessed portion 214, and/or or from an interior side ofanother suitable portion of the lens holder 212. The protrusions areconfigured to snugly contact one or more selected geometric features onthe image sensor package to thereby align the lens holder (and thus anylenses in the lens holder) with the image sensor package an imagesensor. It will be understood that first protrusion 216 and secondprotrusion 218 are shown for the purpose of example, and that any othersuitable alignment feature may be used. For example, instead of aprotrusion, an alignment feature may comprise a notch configured toaccommodate a complementary geometric feature on the image sensorpackage.

As mentioned above, the alignment features (e.g. first protrusion 216and second protrusion 218 in the depicted embodiment) are configured tocontact the image sensor package 204 to mechanically align the lensholder 212 with the image sensor package 204. This is illustrated inFIG. 3. In this figure, it can be seen that the alignment features ofthe lens holder 212 are complementary to the geometrical sensor packagefeatures of the image sensor package 204 such that the first protrusion216 and second protrusion 218 fit snugly about the image sensor package204.

The alignment features may be configured to contact any suitablegeometric structures on the image sensor package. For example, in someembodiments, the alignment features may be configured to mechanicallyalign the lens holder 212 by contacting the image sensor package coverplate 208. In other examples, the alignment features may be configuredto mechanically align the lens holder 216 by contacting the sensorpackage datum corner 212, or both the datum corner and the image sensorpackage cover plate. Further, yet other embodiments may utilize othergeometric features of the sensor package cover to align a lens in a lensholder to an image sensor. Additionally, in other embodiments, a lensholder may comprise a recessed portion without protrusions (e.g. wherethe entirety of the recessed portion is sized to fit snugly over theimage sensor package).

The alignment features may be formed in any suitable manner. Forexample, depending upon how the lens holder 212 is constructed, thealignment features may be machined into the lens holder, cast or moldedas a part of the lens holder, or bonded to the lens holder as aseparately formed piece. It will be understood that these methods offorming the alignment features are described for the purpose of example,and are not intended to be limiting in any manner.

FIG. 4 shows an embodiment of a method 400 for aligning a lens holderwith an image sensor package mounted on a printed circuit board, wherethe lens holder includes one or more lenses and one or more alignmentfeatures, and the image sensor package includes an image sensor and oneor more geometrical sensor package features.

Method 400 comprises, at 402, placing the lens holder proximate to theimage sensor package, and then aligning the lens holder to the imagesensor package by contacting the one or more alignment features of thelens holders with the one or more geometrical sensor package features at406. For example, in some embodiments, this may comprise contacting oneor more alignment features with an image sensor package cover plate at408. In other embodiments, this may comprise contacting the one or morealignment features with a sensor package datum corner at 410.

At 412, the method 400 includes fixing the lens holder to one or more ofthe image sensor package and the printed circuit board. At 414, themethod 400 may further include placing the lens holder and printedcircuit board into a depth-sensing camera, or a webcam, or in any othersuitable optical device. Due to the tight tolerances of the geometricalfeatures of the lens holder and the image sensor package, it will beunderstood that the lens holder and printed circuit board may be placedinto the optical device without performing any additional lens-to-sensoralignment processes, such as active alignment processes, after fixingthe lens holder to the image sensor package and/or the printed circuitboard. It will be understood that the order of the individual processesof method 400 is presented for the purpose of example, and that theillustrated processes may be performed in any other suitable order. Asan example, the lens holder and/or printed circuit board may be placedinto a depth-sensing camera before alignment of the lens holder and theimage sensor package.

It will further be understood that the configurations and/or approachesfor aligning a lens with an image sensor in an optical device describedherein are exemplary in nature, and that these specific embodiments orexamples are not to be considered in a limiting sense, because numerousvariations are possible. The specific routines or methods describedherein may represent one or more of any number of processing strategies.As such, various acts illustrated may be performed in the sequenceillustrated, in other sequences, in parallel, or in some cases omitted.Likewise, the order of any of the above-described processes is notnecessarily required to achieve the features and/or results of theembodiments described herein, but is provided for ease of illustrationand description.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various processes,systems and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. An optical system, comprising: a printed circuit board; an imagesensor package mounted on the printed circuit board, the image sensorpackage including an image sensor; and a lens holder including: a lens,and one or more alignment features arranged on the lens holder, whereinthe one or more alignment features are configured to contact the imagesensor package to mechanically align the lens holder with the imagesensor package.
 2. The system of claim 1, where the one or morealignment features are located within an inside of the lens holder. 3.The system of claim 2, where the one or more alignment features includea recessed portion of the lens holder, the recessed portion having oneor more protrusions arranged on an inside surface of the recessedportion.
 4. The system of claim 1, where the one or more alignmentfeatures are complementary to one or more geometrical features of theimage sensor package.
 5. The system of claim 1, where the image sensorpackage includes an image sensor package cover plate, and where the oneor more alignment features are configured to mechanically align the lensholder with the image sensor package cover plate.
 6. The system of claim1, where the image sensor package comprises a sensor package datumcorner, and where the one or more alignment features are configured tomechanically align the lens holder with the image sensor package datumcorner.
 7. The system of claim 1, where the optical system comprises adepth-sensing camera.
 8. The system of claim 1, where the optical systemcomprises a webcam.
 9. A method for aligning a lens holder with an imagesensor package mounted on a printed circuit board, the lens holdercomprising one or more lenses and one or more alignment features, theimage sensor package comprising an image sensor and one or moregeometrical sensor package features, the method comprising: placing thelens holder proximate to the image sensor package; aligning the lensholder to the image sensor package by contacting the one or morealignment features of the lens holders with the one or more geometricalsensor package features; and fixing the lens holder to one or more ofthe image sensor package and the printed circuit board.
 10. The methodof claim 9, where contacting the one or more alignment features with theone or more geometrical sensor package features comprises contacting theone or more alignment features to an image sensor package cover plate.11. The method of claim 9, where contacting the one or more alignmentfeatures with the one or more geometrical sensor package featurescomprises contacting the one or more alignment features to a sensorpackage datum corner.
 12. The method of claim 9, further comprisingplacing the lens holder and printed circuit board into a depth-sensingcamera.
 13. The method of claim 12, further comprising placing the lensholder and printed circuit board into the depth-sensing camera withoutperforming any additional lens-to-image sensor alignment processes afterthe fixing of the lens holder to the one or more of the image sensorpackage and the printed circuit board.
 14. The method of claim 12,wherein the lens holder and printed circuit board are placed into thedepth-sensing camera before fixing the lens holder to the one or more ofthe image sensor package and the printed circuit board.
 15. The methodof claim 9, further comprising placing the lens holder and printedcircuit board into a webcam.
 16. A camera, comprising: a printed circuitboard; an image sensor package mounted on a printed circuit board, theimage sensor package comprising an image sensor and an image sensorpackage cover plate, the image sensor package comprising a sensorpackage datum corner; and a lens holder including: a lens, and one ormore alignment features located on an interior side of the lens holder,wherein the one or more alignment features are complementary to one ormore of the image sensor package cover plate and the sensor packagedatum corner, and wherein the one or more the alignment featuresconfigured to mechanically align the lens holder with the image sensorpackage based on contact between the alignment features and the one ormore of the image sensor package cover plate and the sensor packagedatum corner.
 17. The camera of claim 16, where the one or morealignment features are arranged within a recessed portion of the lensholder.
 18. The camera of claim 17, wherein the one or more alignmentfeatures comprise one or more protrusions arranged on an inside surfaceof the recessed portion.
 19. The camera of claim 16, wherein the camerais a depth-sensing camera.
 20. The camera of claim 16, wherein thecamera is a webcam.